ok i recently replaced the fuel cap on my 91 rs.. its a 3.1 v6. that triggered the ses light and now my car has almost no power tryed the old cap and no change... it sounds great still no misses or anything just no power anymore... any ideas?



oh and there are no vacuum leaks the maf is good

 

Do a full tune up and see what happens. BTW, the 90-92 cars don't have a MAF, they have a MAP (bolted to a bracket bolted to the cowl by the heater/A/C box).

 

sorry ment map, didnt think it looked like a maf, (work aircraft by trade not cars). tune up was recently done i pulled the code its a 43, low voltage at electronic timing circuit, i ohmed my coil and pickup coil check the wires and plugs and its all good.. any other ideas?

 

Code 43 has nothing to do with the ignition system, really. Code 43 means a spark control (ESC, Electronic Spark Control) fault, which means a bad sensor (round thing screwed into the block by the starter), faulty/melted/shorted to ground wire, bad connection, or a bad ESC board in the ECM calibrator module, or the ECM itself. Check the wire coming out of the knock sensor by the starter to make sure it's not cut, melted, or damaged in any way. The sensor connector is pointing straight out of the engine block down by the starter solenoid, and has a blue wire attached to a plastic connector you have to squeeze to remove. And you MUST disconnect the battery when you remove the sensor, as the sensor could end up shorting out the battery when removed (it's only about half an inch from the positive battery terminal on the starter solenoid). Also, have the new one ready to go in if you're going to replace the sensor, because the KS also acts as the passenger's side engine block coolant drain plug.

If a code 43 is present, the ECM will run on a separate timing scale compared to a normal system, and overall performance will be affected due to the retarded ignition timing.

 

ok i replaced my knock sensor and all the wires are good my car runs way better now, that things was definitely bad, but im still getting a 43 so that leaves an engine knock, but i cant seem to figure it out any help?

 

did you reset the code? disconnect batter to clear codes and see if it comes back after that

 

yup tried that to no avail

 

Pull the spark plugs and see if any have detonation damage. If you see one, you'll know. If not, you'll need to go fishing behind the dash and dig out the ECM to make sure the wiring is good. Make sure all of the terminals are pushed into the connectors all the way.

Did you check to make sure that the wire for the KS isn't getting burned on the exhaust or by the exhaust? Have you done any other work to the car recently that could cause this, such as replacing some part that could be pinching the KS signal wire?

 

okay heres the latest... no detonation damage as far as i can tell i got an oil change and added so high mileage additive (slick 50 i think) and the engine light went away that was about 4 days ago well about 200 miles down the road (not all at once) it pops back up and my car runs bad again... any more ideas it was suggested that i have a build up of sludge or something that could be causing the knock but idk

 

I would say its fuel related if the gas cap change did it as you say.

If the new cap sealed right or better, maybe it put a strain on an old fuel pump?